Apex domains cannot have CNAME records.
Question and response
Question
dig telium.com.br. NS
Answer
telium.com.br. 3 NS ns1.telium.com.br.
telium.com.br. 3 NS ns6.telium.com.br.
telium.com.br. 3 NS ns3.telium.com.br.
telium.com.br. 3 NS ns2.telium.com.br.
Authority
The response has no authority records.
Additional
ns1.telium.com.br. 3 A 200.201.133.2
ns2.telium.com.br. 3 A 200.201.158.74
ns3.telium.com.br. 3 A 200.155.159.124
ns6.telium.com.br. 3 A 98.81.98.83
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0